Rare tropical fungus infection on the rise in the Northwest but risk of infection low

A deadly fungus that in the past primarily affected people in tropical and subtropical regions is causing a growing number of infections in the Northwest, the U.S. Centers for Disease and Prevention (CDC) reports.

The spores of the fungus, Cryptococcus gattii, are known to be able to colonize the nasal cavity and then spread to other parts of the body, causing meningitis and pneumonia, and forming large tumor-like masses in the lung, brain, and muscles called cryptococcomas, the CDC said.

Until 1999, most human cases were seen in tropical and subtropical regions, including parts of Africa, Asia, Australia, the Mediterranean, South America, and southern California.

Then in 1999 cases of infection began appearing on Vancouver Island and in 2004 on mainland British Columbia. In that same year, a case was reported in Oregon that was linked to an outbreak in Canada.

The following year, 2005, another case was reported in oregon, and 12 more in 2006 and 2007.

Studies in Vancouver have found the fungus’s spores in the environment in association with trees and soil. In the U.S., before 2004, the fungus has been identified in the environment only rarely, the CDC said.

In this week’s issue of the CDC’s publication MMWR (Morbidity & Mortality Weekly Report), researchers from the Cryptococcus gattii Public Health Working Group describe 60 cases that have been identified in the U.S. since 2004: 43 from Oregon, 15 from Washington, one from California, and one from Idaho.

Dr. Emilio DeBess, DVM of Oregon Public Health was the report’s lead author.

FIGURE. Cases of Cryptococcus gattii infection* (n = 51) with known illness onset date,† by quarter — California, Idaho, Oregon, and Washington, 2004–2010

“Among 52 patients for whom travel history was known, 46 (88%) said they had not traveled to British Columbia or any other C. gattii–endemic areas, suggesting they acquired the infection locally,” the researchers report.

“Among the 45 patients for whom outcome was known, nine (20%) died because of C. gattii infection and six (13%) died with C. gattii infection,” the researchers said.

Another species of the fungus, Cryptococcus neoformans, commonly causes infections in people with severely suppressed immune systems, such as people infected with HIV.

“Among 47 patients (with Cryptococcus gatti infections) for whom such information was known, 38 (81%) had an underlying condition that might have predisposed them to infection, including three patients with HIV infections,” the researchers found, but two of the nine who died from the infection had no known predisposing condition.

In an editorial comment, CDC officials said the risk factors for infection in the United States appear to include both immunocompromise and exposure to specific regions of environmental fungal colonization.

The fungus may now be appearing in a temperate climate either because it has adapted to a new climatic niche, or because of climate warming has made it possible for the its spores to survive and propagate in these regions, the CDC said, though it is possible infections had occurred in the past that had not been identified.

“Physicians should consider C. gattii as a possible etiology of infection when treating patients (particularly those who are HIV negative) who have signs and symptoms of cryptococcal infection, and should ask patients about recent travel to the Pacific Northwest, British Columbia, or other C. gattii–endemic areas,” the CDC said.

Information on Cryptococcus gattii from the CDC’s website:

Cryptococcus gattii

Who gets Cryptococcus gattii cryptococcosis?

Cryptococcosis is the disease caused by the fungus Cryptococcus. Infections with C. gattii have occurred in both healthy persons without compromised immune systems and in persons with conditions affecting their immune system. A wide range of animals can also develop C. gattii cryptococcosis.

How is Cryptococcus gattii spread?

C. gattii spores appear to live in association with certain trees and the soil around trees. Humans can become infected by inhalation of airborne fungi which are spread from these sources.

C. gattii cryptococcosis is not known to be spread from person to person, animal to animal, or from animals to humans.

What are the symptoms of a infection with Cryptococcus gattii?

Infection with C. gattii may cause a pneumonia-like illness, with shortness of breath, coughing, nausea, and fever. Another common form of C. gattii infection is central nervous system infection, such as meningoencephalitis. Symptoms may include fever, headache, or a change in mental status.

How soon do symptoms of Cryptococcus gattii infection appear?

Symptoms from C. gattii infection are estimated to begin anywhere from 2-14 months after exposure.

If I have symptoms, should I see my doctor?

Yes, it is very important to seek immediate medical evaluation.

How is an infection with Cryptococcus gattii diagnosed?

The diagnosis can be made by microscopic examination and/or culture of tissue or body fluids such as blood, cerebrospinal fluid and sputum. The cryptococcal antigen test is a rapid test that can be performed on blood and/or cerebrospinal fluid to make the diagnosis. Culture of the organism is essential to differentiate between the two species, but Cryptococcus gattii cannot currently be distinguished fromCryptococcus neoformans without special laboratory testing available at CDC and at some state health department laboratories.

How are Cryptococcus gattii infections treated?

Treatment of meningoencephalitis and other severe cryptococcal infections is usually initiated with amphotericin B, often with flucytosine. Fluconazole is used for maintenance therapy in HIV-infected patients with cryptococcal meningoencephalitis, and may be used for patients with milder forms of infection not involving the central nervous system. Treatment of C. gattii sometimes requires prolonged therapy. Guidelines for treating cryptococcal infections are available at the Infectious Diseases Society of America website.

How can Cryptococcus gattii infections be prevented?

There are no formal recommendations for the prevention of C. gattii infection. However, patients with signs and symptoms of infection are urged to see their physician.

To learn more:

• Read the full MMWR article.

• Go to the U.S. Centers for Disease Control Cryptococcus information page.

• Go to the Washington State Department of Health’s Cryptococcus fact sheet.

Tags: CDC, Cryptococcus gattii

Category: Infections, News